Rolando Paksas was the first European president to be impeached. He was also the third president of Lithuania after it seceded from the Warsaw pact. According to wikipedia:
During his term, concerns arose that he had ties to the Russian mafia. Yuri Borisov, president of the aviation company Avia Baltika, had donated $400,000 to his campaign, and was given Lithuanian citizenship by Paksas' decree. This decree was later ruled to be unconstitutional by Constitutional Court of Lithuania.
Paksas' connections were investigated by the Department of Security. In early 2004, the Seimas [Lithuanian Parliament] started impeachment proceedings against him. On 31 March 2004 the Constitutional Court of Lithuania found him guilty of violating the constitution and his oath of office. On 6 April 2004, the Parliament (Seimas) voted on three charges:
a. that he had leaked classified information about his investigation to Borisov
b. that he had improperly restored Borisov's citizenship
c. and that he had interfered in a privatization transaction.
Euroactiv also notes:
Out of the minimum of 85 votes needed of the 141-seat parliament, 86 MPs voted that Paksas illegally granted Lithuanian citizenship to Borisov and leaked state secrets. 89 deputies voted that he improperly meddled in a privatisation deal.
What was the nature of this interference in a privatisation transaction?